Top Cloud-agri KDN Series Semi-Automatic Kjeldahl Nitrogen Determinator

Overview

The Top Cloud-agri KDN Series Semi-Automatic Kjeldahl Nitrogen Determinator is a precision-engineered system designed for reliable quantification of total nitrogen content in organic and inorganic samples via the classical Kjeldahl digestion and steam distillation method. Developed in strict adherence to internationally recognized analytical protocols—including AOAC Official Method 984.13, ISO 5983-1:2009, and ASTM D1122—this instrument delivers traceable, reproducible results across diverse matrices such as cereals, feedstuffs, dairy products, soil extracts, pharmaceutical intermediates, and environmental samples. Unlike fully automated systems requiring proprietary reagents or complex calibration routines, the KDN Series maintains operational transparency through manual sample loading and endpoint titration while integrating microprocessor-controlled distillation logic, real-time water-level monitoring, and fail-safe thermal management. Its modular architecture supports seamless integration with standard laboratory titration setups (e.g., burettes or autotitrators) and accommodates both distilled water and municipal tap water supply—reducing dependency on auxiliary purification infrastructure.

Key Features

• Microcontroller-based process control enabling precise timing of digestion reflux, alkalization, steam generation, and condensate collection
• Dual water supply compatibility: accepts either tap water (≤20°C inlet temperature) or pre-purified distilled water, minimizing operational constraints in resource-variable labs
• Integrated safety interlocks including digestion tube safety door sensor, boiler low-water cutoff, and real-time water-level fault detection with audible/visual alerts
• Corrosion-resistant construction: powder-coated steel chassis with ABS polymer front panel rated for sustained exposure to H₂SO₄, NaOH, and boric acid vapors
• Adjustable distillation cycle duration (5–15 min/sample) optimized for sample mass and matrix complexity, ensuring complete ammonia liberation without overdistillation
• Standardized 4-, 8-, 12-, or 20-position digital programmable graphite or electric digestion blocks—each calibrated to maintain ±2°C thermal uniformity across all wells

Sample Compatibility & Compliance

The KDN Series is validated for use with solid, semi-solid, and liquid specimens conforming to established Kjeldahl applicability criteria. Solid samples (e.g., flour, soybean meal) are limited to 2.00 g maximum; semi-solids (e.g., cheese, sludge) up to 5.00 g; and liquids (e.g., milk, urine, digest filtrates) within 10.00–25.00 mL volume range. All configurations meet GLP documentation requirements when paired with external audit-trail-capable titrators. The system’s ≥99% nitrogen recovery rate satisfies AOAC performance benchmarks for method validation, while its RSD < ±1% repeatability meets ISO 5725-2 precision criteria for intermediate precision under routine lab conditions. No modifications to digestion chemistry (e.g., catalyst composition or acid concentration) are required to achieve compliance with USP , EP 2.5.2, or FDA 21 CFR Part 11–aligned data handling workflows.

Software & Data Management

As a semi-automatic platform, the KDN Series does not incorporate embedded data logging or proprietary software. Instead, it provides standardized analog/digital I/O interfaces (RS-232 optional) to integrate with third-party LIMS or ELN environments. Operators record distillation start/end times, sample IDs, and titrant volumes manually or via connected autotitrators supporting ASTM E2655-compliant result export. All hardware control logic resides in hardened firmware with immutable parameter sets—eliminating version drift risks associated with frequent software updates. Calibration certificates for digestion block temperature profiles and steam flow linearity are supplied with each unit and remain valid for 12 months under normal operating conditions.

Applications

• Protein content estimation in agricultural commodities using standard nitrogen-to-protein conversion factors (e.g., 6.25 for cereal grains, 6.38 for dairy)
• Regulatory testing of animal feed formulations per EU Regulation (EC) No 152/2009 Annex VI
• Quality control of nitrogen fertilizers and industrial ammonium salts
• Environmental monitoring of total Kjeldahl nitrogen (TKN) in wastewater and sediment digests per EPA Method 351.2
• Pharmaceutical excipient qualification where residual ammonium sulfate or urea must be quantified prior to API synthesis
• Academic research involving nitrogen balance studies in plant physiology or microbial metabolism assays

FAQ

What digestion block configurations are available?
The KDN Series offers four standard digestion module options: 4-hole digital electric, 4-hole graphite, 8-hole digital electric, 8-hole graphite, 12-hole digital electric, and 20-hole digital electric—each shipped pre-calibrated and compatible with standard Kjeldahl digestion tubes (250 mL capacity).
Is the system compliant with 21 CFR Part 11 requirements?
While the base instrument lacks electronic signature or audit trail functionality, it is fully compatible with FDA-regulated workflows when used alongside Part 11–compliant titration systems and LIMS platforms that manage user authentication, change control, and electronic record retention.
Can the unit operate continuously for high-throughput labs?
Yes—thermal management and boiler duty cycle are engineered for sequential processing of up to 40 samples per 8-hour shift, assuming standard 10-minute distillation cycles and proper cooling water flow (3 L/min minimum).
What maintenance intervals are recommended?
Monthly inspection of steam trap integrity, quarterly descaling of boiler chamber using 5% citric acid solution, and annual verification of water-level sensor accuracy using NIST-traceable level gauges.
Does the system require external vacuum or compressed air?
No—steam generation, condensate collection, and distillate delivery rely solely on gravity-fed water supply and internal pressure differentials; no ancillary gas or vacuum sources are needed.